In recent years, in overseas countries (in particular, the European market), there is a need for an electric motor vehicle adaptable to various overhead wire voltages (e.g., AC15 kV-16.7 Hz, AC25 kV-50 Hz, DC1.5 kV, and DC3.0 kV) according to the unification of railroad networks in Europe and an increase in environment consciousness. It is desired to equip an electric motor vehicle main circuit system adaptable to such a multiple power supply.
On the other hand, the applicant performed document searches for technologies concerning an electric motor vehicle main circuit system adaptable to a plurality of multiple power supplies by an alternating current and a direct current like the multiple power supply explained above, more specifically, both of an alternating-current power supply and a direct-current supply and adaptable to an AC-DC multiple power supply in which at least one of the alternating-current power supply and the direct-current power supply is provided in a plural form. However, the inventor has not found an appropriate document including the related art. The “plural” in this context means that both of the direct-current power supply and the alternating-current power supply are distinguished according to a difference in an overhead wire voltage.
Note that, if reference documents are presented concerning the technology explained above, there are Patent Literatures 1 and 2. Patent Literature 1 discloses a technology for unitizing devices in a control device to attain a reduction in a work time and a restoration time from a failure. Patent Literature 2 discloses a technology for securing compatibility among units in a control device to solve a problem of an inductive interference when the units are manufactured by a plurality of manufactures.